1. Field of the Invention
The invention relates generally to a compass and particularly to a dry compass. More particularly, it relates to a compass which is used as an ornament as well.
2. Description of the Prior Art
Ordinary compasses comprise just a bar magnet and a gage plate as a dry type compass or comprise a gage sphere having a magnet therein which is put in liquid as the liquid type compass. Since the liquid type compass has problems such as chemical corrosion by the liquid and thermal expansion, the present invention is the dry type.
In the dry type, there is a PCT patent application in Japan, the application number of which is JP84/00389, and the inventer of which is the same one as that of the present invention.
The prior art is a dry type compass comprising a cubic molding such as a toy car, a gage plate showing directions and a map, and a pair of magnets one of which is a low-powered magnet which is attached to the cubic mold and the other of which is a high-powered magnet which is mounted outside of the cubic mold.
Since the construction of the dry type compass has the compass needle mounted on a pin type support, it is very difficult to adjust the center of the gravity of the needle.
Even if it can be adjusted perfectly, its north side will go down in the Northern Hemisphere and its south side will go down in the Southern Hemisphere because of the magnetism of the Poles of the earth.
Of course, since mass and weight of ordinary compasses are small and light, it is not a big problem though it is clumsy. However, it will be a big problem, if the compass is used as an ornament.
A compass having a pair of magnets as described in the prior art is high in price and will not fluctuate. Thus, this prior art compass will not show interesting motions. Also, the other compasses will not fluctuate either.
The prior art compasses have the same problem with regard to the direction in which the compass needle points since the position of the north Pole and the South Pole of the earth is a little bit different from the positions to which prior art compasses point to.